FIVE POINTS OF ANIMAL HEALTH EVALUATION: DIGESTIVE HEALTH

By Jose Valles, MS, Production Animal Consultation

In the fall 2021 issue of Protein Producers , we began to talk about a five-point animal health evaluation that I like to implement when working with animal caregivers in the area of pen riding in feedyards. This evaluation not only consists of detecting cattle that may need medical attention but also helps promote animal health in the lameness, digestive, respiratory, neurological, and mental categories. In the fall, we discussed the lameness category; in this article, we will address the most common digestive issues.

When we enter a pen of cattle, it is important to get all cattle up and ask them to move a reasonable distance or time that will allow us to make a careful digestive evaluation. The distance or time the animal is asked to be in motion should be sufficient to cause the animal to pass manure. Observation of the sides and the abdominal area of the animal is essential. The fill of paralumbar fossa region can give us an idea if the animal has been eating and drinking and is also the anatomical area that presents clinical signs of tympany. Evaluation of fresh stools provides important information for digestive health evaluation for individual animals or at the pen level. Fresh manure characteristics such as consistency, color, and odor can help in reaching a diagnosis. Taking notes of clinical signs presented by the animal in its home pen is highly recommended. This information will help the doctor with case definition, diagnosis, and treatment.

Some of the most common digestive issues in a feedlot include ruminal acidosis, infectious diseases like coccidiosis and salmonellosis, and tympany.

Cattle are such special herbivores because they have the ability to convert cellulose from grasses that are nonusable for human consumption into nutritional beef for human consumption. Over the years, the beef industry has adapted different types of cattle feeding programs for beef production. Feedlot confinement settings for grain fed cattle are the most popular feeding program. Ruminal acidosis is a disease commonly seen in feedlot settings during the initial phase of the animals’ feeding period. Nutrition programs vary between feedlots, their consulting nutritionists, and the availability of resources within their area. Cellulose from grasses ferments slowly in the rumen while our most common feed ingredients such as corn, wheat, sorghum, and barley are highly fermentable. These highly fermentable ingredients produce volatile fatty acids and lactic acid at a much faster rate, producing a lower ruminal pH. Drastic changes in diets such as change in amount delivered, ingredients, concentration, consistency, or timing can cause acidosis in cattle. The objective is to adapt cattle from a lower concentration diet to a higher concentration diet over the shortest period of time possible without causing digestive discomfort. This requires lots of monitoring and communication from our feeding crew as well as our animal health teams. Some of the most evident clinical signs of acidosis include diarrhea, excessive clear salivation, and hesitation to move. In situations of subacute acidosis, implementation of additional water tanks, forage, and cattle exercise can help regulate ruminal content without making major changes in diet. In cases of acute acidosis, implementation of the previously mentioned strategies is critical as well as a change in the fed diet. It is always advisable to pull some of the most affected individuals for chute side evaluation to determine if antibiotic use is needed.

Coccidiosis is an infectious disease caused by the coccidia parasite that affects the infected animal’s intestinal tract. There are several species of the parasite but not all cause disease. Eimeria and Isospora are two disease-causing species. Eimeria and Isospora are passed in manure as a non-infectious oocyst. Within 5 to 10 days, under the right environmental conditions, the oocyst transforms into an infectious form, which can then be ingested by cattle. Once in the digestive system of the animal, the oocyst releases a sporozoite, an infective agent that penetrates intestinal cells. The sporozoite goes through a growth and reproduction cycle repeatedly over a 21- to 28-day period, damaging the lower intestines, cecum, and colon and producing an oocyst that will be passed through manure. Although cattle in feedlot settings are susceptible to coccidiosis throughout their feeding period, outbreaks are more likely to occur during the first 30 days post arrival. Mild cases of coccidiosis usually present with foul-smelling, dark diarrhea, while moderate to severe cases usually present bloody diarrhea. Infected animals can appear depressive, reduce feed consumption, and become dehydrated, which leads to weight loss.

Ruminal tympany, better known in feedlots as bloat, is another digestive disease that commonly affects cattle in confinement. Bloat is the overdistention of the rumen and reticulum caused by the accumulation of gases produced in the rumen during the process of microbial fermentation. Bovine normally expel these gases by eructation. There are two types of bloat in cattle, the primary form and the secondary form.

The primary form, also known as frothy bloat, occurs when ruminal gases mix with ruminal contents in a stable foam and cannot be eructated. Primary ruminal tympany commonly appears in feedlot settings due to the high levels of ground grain fed to cattle. The rapid digestion of these small feed particles produces bubbles of trapped gas and particular species of ruminal bacteria produce an insoluble slime that develops into a stable foam.

The secondary form of ruminal tympany, commonly known as free-gas bloat, results when the bovine cannot eliminate ruminal free gas due to an esophageal obstruction. The cause of obstruction varies and is often never determined. It can be a result of ingested foreign objects, hernias, tumors, abscesses, and other lesions.

When evaluating cattle for digestive abnormalities, it is important to consider general pen information such as days on feed, the ration being fed, and ration transition history. Animals that present digestive abnormalities or overdistention in the paralumbar fossa and/or abdominal area that make them look different from the rest of the group deserve to be pulled and evaluated chute side to determine the appropriate treatment or mitigation strategy to be implemented. Keep in mind that the timing of our pulls will significantly impact our treatment success rates.

Resources

Constable, PD. Bloat in Ruminants. Merck Veterinary Manual. June 2016. https://www.merckvetmanual.com/digestivesystem/diseases-of-the-ruminant-forestomach/bloat-inruminants

Constable, PD. Coccidiosis of Cattle. Merck Veterinary Manual. June 2016. https://www.merckvetmanual.com/ digestive-system/coccidiosis/coccidiosis-of-cattle

Kvasnicka, B. Coccidiosis in Beef Cattle. Extension Beef Cattle Resource Committee, Beef Cattle Handbook BCH3300. https://www.iowabeefcenter.org/bch/Coccidiosis.pdf http://www.vivo.colostate.edu/hbooks/pathphys/digestion/ herbivores/acidosis.html http://www.vivo.colostate.edu/hbooks/pathphys/digestion/ herbivores/tympany.html

Ruminal Acidosis (Grain Overload). Colorado State University, VIVO Pathophysiology. January 2020.

Ruminal Tympany (Bloat, Hoven). Colorado State University, VIVO Pathophysiology. January 2020.

Jose Valles graduated with his Master of Biomedical Sciences from Kansas State University in 2013. He was born in the state of Durango in Mexico. He spent his childhood in both Durango and in southwest Kansas. In Mexico, his family has been dedicated to a cow-calf operation and the farming of dry beans, corn, and oats. After high school, Jose decided to further his education at the university level and has since lived in the U.S. He attended Seward County Community College in Liberal, Kansas, and during that time worked at the Liberal Animal Hospital. Jose transferred to Kansas State University through the Developing Scholars Program and Bridges to the Future Program. While attending Kansas State University, Jose worked at the Beef Cattle Institute from 2007 to 2013. After graduating from Kansas State University in 2013, Jose joined the PAC team, then later that year married his girlfriend Areli, and moved to Kearney, Nebraska. Jose enjoys spending time with his beautiful wife Areli and his sons Matteo and Antonio. He also enjoys riding a good horse, horse races, and grilling steaks.